Preliminary Study On The Efficiency And Mechanism Of Pulse Electroflocculation For Treatment Of Heavy Metals Source Water

Water Treatment Plants' facilities and the management level are relatively backward in rural areas of China.It is difficult to maintain the management and operation of Water Treatment Plants.Therefore,the water quality and quantity of the Water Treatment Plants do not match the drinking water demand of the rural residents.In recent years,rural drinking water resources have been deteriorating year by year,among which heavy metal pollution is a prominent problem.Pulse electroflocculation,as an economical and practical water treatment technology with simple maintenance and management,is suitable for rural drinking water treatment.This paper mainly studies on the efficiency of pulse electroflocculation for treatment of rural heavy metals source water.The pulsed electrocoagulation was used to treat the water containing heavy metals.The influence of pulsed electrocoagulation parameters on the removal efficiency of heavy metals was investigated.The optimum process parameters of pulsed electroflocculation for the removal of heavy metals such as copper,zinc,lead and cadmium were obtained.When the plate material is aluminum anode iron cathode,the plate spacing is 0.5cm,the positive pulse duty is 40%,the positive pulse frequency is 100 Hz,the negative pulse duty is 10%,the negative pulse frequency is 100 Hz,the working time of positive pulse is 1000 ms,the working time of negative pulse is100 ms,the positive pulse peak voltage is 25 V,and the negative peak voltage is4 V,the removal of Cu2+,Zn2+,Pb2+ and Cd2+ is the best.The removal rates of copper,zinc,lead and cadmium in the effluent were 99.87%,91.62%,99.00%and 94.00%,respectively.The concentration of heavy metals in the effluent was in line with the sanitary standard for drinking water.Under the optimal parameters,the pulse electrocoagulation device was operated to investigate the adaptability of the water quality containing heavy metals and the mechanism.It was found that when the influent water p H range of the was 7-8,the influent flow was less than 214.2ml/min,the concentration of heavy metals in the influent water was less than 20 times of the sanitary standard for drinking water(GB5749-2006),the pulse electrocoagulation process can be widely used to remove copper,zinc,lead and cadmium.Use pulse electroflocculation treat the actual water containing heavy metals.The concentrations of Cu2+,Zn2+,Pb2+ and Cd2+ in the effluent were 0.012mg/l,0.037mg/l,0.001mg/l and 0.002mg/l,respectively.The removal rates of heavy metals were 99.88%,99.63%,99.00% and 96.00% respectively.The pulsed electroflocculation plant handles 1 ton of water,consumes 56.07 g aluminum anode,1.12 g iron cathode and 0.78 k W·h electrical energy.The material and electricity cost is 1.32 yuan in total.The experimental results of this project show that it is feasible to treat the source water containing heavy metals in rural areas by pulse electrocoagulation.The water quality index of heavy metals in treated water meets the requirements of the sanitary standards of drinking water(GB5749-2006).